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Aggressive differentiated thyroid cancer with multiple metastases and NRAS and TERT promoter mutations: A case report.

ABSTRACT: Sorafenib, a tyrosine kinase inhibitor, is approved for the treatment of advanced differentiated thyroid carcinoma (DTC). Resistance to sorafenib may appear under treatment and may be associated with increased aggressiveness of the neoplasia. The present study reports the case of a 65-year-old male who underwent total thyroidectomy for a follicular thyroid carcinoma, Hürthle cell variant, in February 2005. Until January 2010, the patient received four consecutive 131I doses (total dose, 612 mCi) for increased serum thyroglobulin (Tg) and initial faint lung uptake (which eventually became undetectable). Subsequently, the patient developed several sequential bone (humerus, rib and skull), adrenal and lung metastases, the majority of which were surgically removed. Histological examination in all cases revealed evidence of DTC metastases that were strongly positive for Tg, as revealed by immunohistochemistry. In March 2014, sorafenib therapy was initiated, but it was discontinued 10 months later to allow an undelayable prostatectomy. Immediately upon surgery, the patient developed a large metastatic lesion in the right gluteal muscle, whose biopsy revealed undifferentiated neoplasia of epithelial origin, and the patient succumbed shortly afterwards. An extensive comparative search for biochemical and molecular markers was performed on all available tissues (primary tumor, and differentiated and undifferentiated metastases). The primary tumor and all the available metastases exhibited the same molecular oncogenic markers (namely, the RAS mutation p.Q61R and the telomerase promoter mutation C228T). In addition, the undifferentiated metastasis exhibited a p53 mutation. The present study reports a case of a sudden acceleration of DTC metastatic progression following sorafenib discontinuation, which could have been due to the emergence of sorafenib-resistant undifferentiated p53-positive tumor cell clones.

SUBMITTER: Pani F

PROVIDER: S-EPMC5530175 | biostudies-other | 2017 Aug

REPOSITORIES: biostudies-other

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Project description:BackgroundReactivation of telomerase reverse transcriptase (TERT) is an important event in cancer. Two hotspot mutations in the TERT promoter region, c.-124C > T (C228T) and c.-146C > T (C250T), occur in various cancer types including thyroid cancer. They generate de novo binding sites for E-twenty-six (ETS) transcription factors causing increased TERT transcription. The aim of this study was to search for novel TERT promoter mutations and additional mechanisms of TERT activation in thyroid cancer.MethodsWe studied 198 papillary thyroid carcinomas (PTCs), 34 follicular thyroid carcinomas (FTCs), 40 Hürthle cell carcinomas (HCCs), 14 poorly differentiated/anaplastic thyroid carcinomas (PDTC/ATC), and 15 medullary thyroid carcinomas (MTCs) for mutations in an -424 bp to +64 bp region of TERT. The luciferase reporter assay was used to functionally characterize the identified alterations. Copy number variations (CNVs) in the TERT region were analyzed using TaqMan copy number assay and validated with fluorescence in situ hybridization (FISH).ResultsWe detected the hotspot c.-124C > T and c.-146C > T mutations in 7% PTC, 18% FTC, 25% HCC, and 86% PDTC/ATC. One PTC carried a c.-124C > A mutation. Furthermore, we identified two novel mutations resulting in the formation of de novo ETS-binding motifs: c.-332C > T in one MTC and c.-104_-83dup in one PTC. These genetic alterations, as well as other detected mutations, led to a significant increase in TERT promoter activity when assayed using luciferase reporter system. In addition, 5% of thyroid tumors were found to have ≥3 copies of TERT.ConclusionsThis study confirms the increased prevalence of TERT promoter mutations and CNV in advanced thyroid cancers and describes novel functional alterations in the TERT gene promoter, including a point mutation and small duplication. These mutations, as well as TERT copy number alterations, may represent an additional mechanism of TERT activation in thyroid cancer.

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Aggressive differentiated thyroid cancer with multiple metastases and NRAS and TERT promoter mutations: A case report.

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